title: Non-invasive assessment of liver fibrosis with transient elastography (FibroScan®): applying the cut-offs of M probe to XL probe.
abstract: BACKGROUND AND RATIONALE FOR THE STUDY: Limited studies have aimed to define the cut-offs of XL probe (XL cut-offs) for different stages of liver fibrosis, whereas those of M probe (M cut-offs) may not be applicable to XL probe. We aimed to derive appropriate XL cut-offs in overweight patients. Patients with liver stiffness measurement (LSM) by both probes were recruited. XL cut-offs probe for corresponding M cut-offs were derived from an exploratory cohort, and subsequently validated in a subgroup patients also underwent liver biopsy. The diagnostic accuracy of XL cut-offs to diagnose advanced fibrosis was evaluated.
  
  
  RESULTS
  Total 517 patients (63% male, mean age 58) who had reliable LSM by both probes were included in the exploratory cohort. There was a strong correlation between the LSM by M probe (LSM-M) and LSM by XL probe (LSM-XL) (r² = 0.89, p < 0.001). A decision tree using LSM-XL was learnt to predict the 3 categories of LSM-M (< 6.0kPa, 6.0-11.9kPa and ≥ 12.0kPa), and XL cut-offs at 4.8kPa and 10.7kPa were identified. These cut-offs were subsequently validated in a cohort of 147 patients who underwent liver biopsy. The overall accuracy was 89% among 62 patients whose LSM-XL < 4.8kPa or ≥ 10.7kPa. These cut-offs would have avoided under-staging of fibrosis among patients with body mass index (BMI) > 25-30 kg/m2 but not > 30 kg/m2.
  
  
  CONCLUSIONS
  XL cut-offs at 4.8kPa and 10.7kPa were the best estimates of 6.0kPa and 12.0kPa of M probe for patients with BMI > 25-30 kg/m2. Patients with BMI > 30 kg/m² might use M probe cut-offs for XL probe.
authors.affiliation: Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Grace Lai-Hung
authors.initials: GL
authors.lastname: Wong
authors.forename: Julien
authors.initials: J
authors.lastname: Vergniol
authors.forename: Peter
authors.initials: P
authors.lastname: Lo
authors.forename: Vincent
authors.initials: V
authors.lastname: Wai-Sun Wong
authors.forename: Juliette
authors.initials: J
authors.lastname: Foucher
authors.forename: Brigitte
authors.initials: B
authors.lastname: Le Bail
authors.forename: Paul Cheung-Lung
authors.initials: PC
authors.lastname: Choi
authors.forename: Faiza
authors.initials: F
authors.lastname: Chermak
authors.forename: Kwong-Sak
authors.initials: KS
authors.lastname: Leung
authors.forename: Wassil
authors.initials: W
authors.lastname: Merrouche
authors.forename: Henry Lik-Yuen
authors.initials: HL
authors.lastname: Chan
authors.forename: Victor
authors.initials: V
authors.lastname: de Lédinghen
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001706:Biopsy; D002138:Calibration; D003661:Decision Support Techniques; D003663:Decision Trees; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000295:instrumentation* / Q000379:methods / Q000592:standards; D004867:Equipment Design; D005260:Female; D005602:France; D006723:Hong Kong; D006801:Humans; D016014:Linear Models; D008099:Liver / Q000000981:diagnostic imaging* / Q000473:pathology; D008103:Liver Cirrhosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results